| The two-column caving hydraulic support is the key equipment to realize the intelligent mining of top coal caving.In view of the hidden dangers of roof support management and safety production caused by the ’ head up ’ or ’ low head ’ of the top beam of the support in the field working state,based on the working state of support in fully mechanized caving face of Caojiatan Coal Mine,the theoretical analysis,numerical simulation and field test methods are used to study the bearing state of the top beam of the two-column caving hydraulic support,and the relevant intelligent control strategies are proposed.Through a series of related studies,the following main results are obtained :The plane stress model of the two-column caving support is constructed,and the load equation of the top beam of the support is established to analyze the ’ three zones’ of the top beam of the support.Through the study and analysis of the bearing characteristics of the support in the coal caving stage,it is concluded that the external force of the top beam of the support is in the bearing area of the support column under normal conditions.After the support is moved,the roof comes under pressure,and the external load force of the roof beam is in the tensile area of the support balanced jack,which is prone to ‘ head up ’;in the process of coal caving and after coal caving,the external force of the top beam moves forward in the compression area of the support balance jack,and the support has a ’ low head ’ trend.The basic model of the two-column caving hydraulic support is constructed,and the kinematics equation of the support is established by using the kinematics knowledge of the robot.The MATLAB software is used to solve the relationship curve between the length of the support column and the length of the balance jack under the normal working environment,and the fitting equation is analyzed to confirm the length relationship between the two.The three-dimensional model of ZYF21000 / 34 / 63 D hydraulic support is established by using computer three-dimensional design method.The kinematics simulation of the support working process is carried out,and the relationship between the support column and the length of the balance jack is obtained.The numerical values of the two algorithms are compared and confirmed.The actual length of the column and the balance jack is counted through field measurement,and the results are compared according to the data in this paper.When the length of the column is determined,the deviation between the length of the field balance jack and the theoretical balance jack is within 4 %.The corresponding conversion bracket top beam inclination angle is within ± 2°,and it is considered that the working state of the bracket is normal.It is determined that the quantitative target of monitoring and monitoring of the top beam is set as the allowable deviation of the top beam inclination angle ± 2 °.When the support electro-hydraulic control system sends out instructions to intelligently regulate the length of the balance jack,so as to adjust the inclination angle of the support top beam within ± 2 °.The intelligent control mode and control strategy of hydraulic support are proposed,and the intelligent monitoring system of hydraulic support working condition in top coal caving face is upgraded.The experimental research on vibration and power frequency withstand voltage of hardware facilities is carried out,which improves the reliability of products and ensures the safe use of the site.According to the research content,the algorithm,simulation results and monitoring technology are proved to be correct and reasonable by field test in coal mine. |
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